The Government appears to have ruled out a "u-turn" on the controversial issue of software patents despite a last minute plea for a rethink by the country's two largest software exporters, Orion Systems and Jade.

A spokeswoman for Commerce Minister Craig Foss said he did not intend to make further changes to the Patents Bill, which he hoped would pass its second reading in Parliament tonight.

Orion and Jade endorsed a letter sent yesterday by four industry bodies which have been putting heat on the Government to change tack on the future status of software patents.

InternetNZ chief executive Vikram Kumar said society, along with the Institute of Information Technology Professionals, NZrise and the New Zealand Open Source Society, had written to Foss to say the wording of a government amendment to the Patents Bill was "problematic".

Foss announced last month that the Government would amend the Patents Bill by including a clause that critics fear would greatly water-down a proposed ban on software patents.

The clause says the ban would prevent anything from being an invention for the purposes of the Patents Act "only to the extent that a patent or an application relates to a computer program as such".

More than 1000 people have signed an online petition calling for the clause to be changed to reduce the size of the "loophole", while still making it clear that inventions that made use of embedded computer programs could still be patented.

However, government officials are understood to be maintaining the alternative wording would clause more problems than it would solve.

Opponents of software patents say they are generally of poor quality and are predominantly used by multinationals and "patent trolls" to stifle innovation at the expense of young, creative and less-well-heeled firms.